Dual-modulus Prescaler Ciruit Operating At a Very High Frequency

摘要

Dual-modulus prescaler circuit (1) it is designed to operate at high frequency. Such a circuit comprises a dynamic two D- type flip-flop (12, 13), and two NAND logic gates (15, 16) disposed in the negative feedback between the two flip-flops. Two replicon-flop provides an output signal (OUT) when supplied with the clock divided by the input clock signal (CK). The frequency of the output signal is divided, it corresponds to the input clock frequency divided by 2 or 3 as a function of the applied division mode selection signal (divb) to the input of the NAND 1 logic gate 15. The non-inverting output of the second flip-flop is connected to the input of the first flip-flop (12). Agent includes three active branches (branch) 1 dynamic flip flop, and supplies the single inverted output signal. A third flip-flop 14, to supply the mode selection signal to the inverting output, and receives a mode selection signal (div) inverted in input, a non-inverted version of the second flip-flop output signal comprising the three active branches It is supplied by a clock.